Unrolling devices or roll stands which can support a roll of paper or cardboard for feeding the web to a machine for the processing of the web are known in a variety of configurations. Some configurations employ mandrels or axles onto which the roll is threaded and in which the axle is supported on trunnions.
In another configuration, engaging heads or cones are provided which fit into the winding sleeve or core upon which the roll is wound, the support cones being mounted on respective stands which can be moved closer or further apart in the direction of the axis of the roll and of the cones to adjust for different roll lengths and web widths. A typical processing machine for which the unrolling device may be provided can be a transverse cutting machine which severs the web into sheets of given length.
To load the device with a new wound roll, for removing a roll residue including the tubular core and for adjusting the device for different web widths, the displacement of at least one of the stands relative to the other in the axial direction is possible. Depending upon the diameter of the wound roll which is to be accommodated, the clamping cones may have to be raised or lowered on the respective stands.
German patent document 32 07 366 discloses an unrolling device for the purposes described in which the clamping heads which engage the wound roll from opposite ends, can be vertically movable by a lifting device. For this purpose the clamping heads may be mounted on support arms which can be shiftable on a horizontal beam to allow axial adjustment to different roll lengths and for engagement of the roll between the arms and the beam is here vertically shiftable. The support arms can extend in or counter to the direction of travel of the web as cantilever arms from lateral supports.
With heavy wound rolls, high torques are generated with these systems so that the supports for the device must be very massive to render them capable of taking up these torques. As a consequence,, the means for effecting vertical movement of the support arms must be expensive and complex.
A roll-lift stand is disclosed in U.S. Pat. No. 2,346,948 in which behind each of two stand members and in the vertical plane of the axis of the wound roll supported in the stand, a respective hydraulic piston-and-cylinder unit is provided. The movable member of these units, namely the piston, carries a roll over which a cable passes to engage a bearing housing in which the engaging cones are journaled. The apparatus eliminates the drawback of the first-mentioned prior art device with respect to the high torques which result when large rolls are carried but the construction is space-consuming and massive as well.
In U.S. Pat. No. 1,874,904, another roll support device is provided in which the rail-engaging members ride up and down on respective posts which are displaceable by windlasses at the top of each stand. A problem with plural windlasses is, of course, that there may be a disorientation of the two windlasses which can result in a canting of the device and problems as a result thereof.